【作者】 陈树沛；

【导师】 朱丽珺；

【作者基本信息】 南京林业大学 ， 环境科学， 2008， 硕士

【摘要】 随着国民经济的发展和人民生活水平的提高,人们对自己的居住条件要求也不断提高。然而室内建材及建筑装修材料散发出大量的挥发性有机化合物(Volatile organic compounds,简称VOC)严重恶化了室内空气品质,甲醛就是其中常见的一种挥发性有机污染源,已经被世界卫生组织确定为致癌和致畸形物质。膨润土是我国含量丰富的一种黏土矿物,是一种无机微孔材料,由于其结构上的多孔使其具有选择性吸附、催化性能。本文以钙基膨润土为原料,制备了一系列常见的改性膨润土:钠化膨润土、酸化膨润土和有机膨润土,并对其矿物学和物理化学性质进行了测试和表征。通过对原钙基膨润土进行一系列改性,膨润土在结构特征、比表面积、有机碳含量和层间距等方面都发生了变化。分析这些膨润土对甲醛气体的吸附性能发现,膨润土对于甲醛都有一定的吸附性。酸化膨润土对于甲醛的吸附净化效果相对最佳,钠化膨润土和原钙基膨润土次之。膨润土对甲醛的吸附主要是膨润土的表面物理吸附。钙基膨润土和钠化膨润土对于甲醛的吸附可能还源于其表面水膜对甲醛的溶解;酸化膨润土的机理则可能因为表面的酸性和质子以及其层间水可能与甲醛发生质子化作用;有机膨润土除了表面吸附外,对甲醛的“相似相溶”的分配也是其吸附机理之一。CTMAB系列有机膨润土对甲醛的吸附为放热过程,其他类型膨润土的吸附可能为吸热的过程。筛选出效果较好的膨润土(原钙基膨润土、钠化膨润土和酸化膨润土)与光催化技术相结合,制备出TiO2-膨润土,研究其吸附效果。研究发现TiO2膨润土对甲醛的吸附净化分两个阶段:吸附净化和光催化净化,两者相互综合、相互促进。在实验条件下,TiO2钙基膨润土优于TiO2钠基膨润土,酸化膨润土则在此相对较差。最后以酸化膨润土为吸附剂,利用箱体进行中试。酸化膨润土能够有效的吸附甲醛,在短时间内使箱体中的甲醛浓度降低,空气中的甲醛浓度能够达到国家标准以下。在酸化膨润土的吸附容量达到饱和前,酸化膨润土都能够具有很好的吸附效率。综合各种实验数据及理论分析,膨润土是一种优良的治理室内甲醛污染的吸附剂,能够有效的消除室内空气中的甲醛污染,用于室内污染治理将有广阔的应用前景。更多还原

【Abstract】 In recent years, due to the development of economy and the improvement of personal living environment, people demand better and better dwelling condition. But indoor synthetic building materials emit a large number of volatile organic compounds (VOCs) and deteriorate indoor air quality badly. Formaldehyde is a commonly detected VOCs pollutant in the door,irritant and susceptivity, which do the serious harm to many apparatus .It has been listed the material causing cancer and abnormality by World Health Organization. Bentonite is a kind of clay mineral that is abundant in our country. Bentonite is an inorganic microporous material, having the ability of selective adsorption ability due to its unique samdwich structure.In this dissertation, a series of modified bentonites(sodium bentonite, acidation bentonite and organobentonite ) were prepared by calcium bentonite. And the mineralogical and physicochemical properties of these bentonite were tested and characterized. After a series of modify, the structural characteristics, the specific surface area, organic carbon content and interlayer space, and other aspects of the bentonite have undergone changes.The adsorptions to formaldehyde of these bentonites were investigated. Results show that acidification bentonite was the best, sodium bentonite was the better one and calcium bentonite next to it.The adsorption of Bentonite is mainly physical adsorption on the surface of bentonite. The results suggested that sorb effects of calcium bentonite and sodium bentonite were relevant tohydration film. Acidification bentonite may also sorb formaldehyde by because the surface acidity, the proton and its interlayer water. The adsorption of organic bentonite may occur by partition process, too. The adsorption process of CTMAB-organobentonite is liberation of heat, and other types of bentonites may were endothermic process.A series of Ti02-bentonite were prepared by calcium bentonite, sodium bentonite and acidation bentonite. Their photocatalytic degradation behavior of formaldehyde is studied. The result shows that adsorption of Ti02-bentonite formaldehyde was two phases: adsorption and photocatalytic purification. The phases were mutually integrated and promote each other. Ti02 calcium bentonite was better than Ti02 sodium bentonite, the Ti02 acidation bentonite was relatively poor.Finally the pilot-scale study was tried with acidation bentonite. Acidation bentonite can effectively adsorbed formaldehyde in a short time and the concentration of formaldehyde was reduced to the state below standards. Acidation bentonite has efficacious adsorption before saturation.In a word, bentonite is an excellent sorbent for formaldehyde and it has extensive prospect on the treatment of indoor pollutant.更多还原